Reporter: Whatever happened in the lusk house that april afternoon, it unleashed lurid rumors ricocheting through prosser, washington. Linda lusk denies she gave oral sex to her daughter's 14-year-old ex-boyfriend. But she says there were some agonizing confessions she needed to make to her own daughter. She's like, "okay, you know, what you're hearing isn't entirely true, but I did have some inappropriate texting and contact with this kid." I was really angry, but not necessarily with my mom, more at the boy. It's devastating, and it was embarrassing. And I was mortified at the pain that I caused my family. Reporter: Especially her husband, the principal at the town high school, kevin lusk. Late night conversation. She said, "i need to talk to you." It was incredible. I was pretty upset, to say the least. Zillions of questions about what the hell are you thinking? Reporter: And kevin would soon learn there were more than just those text messages. There was a photo sent. She told kevin that, after the teenager repeatedly asked for a photo of her naked, linda sent him a picture in her bra. It's like a kid asking for candy 500 times. You finally go, "here, have a piece." You know? Do I regret it? Was it dumb? Yes. I can't believe I did it. Reporter: Kevin lusk demands of his wife two things. And you better make contact with the police and you better contact his parents because those are the right things to do. Reporter: The next morning, linda calls the boy's mother, heidi frank. She just said, "you know, I'd really like to get together and talk to you. I've grown very fond of your son and we've been texting each other back and forth for the last few months and lately it's gotten inappropriate on my part. I just started thinking, that is the craziest phone call I've ever gotten. Reporter: And as if that jaw-dropping phone call wasn't enough, then came a knock at the door from the prosser police department. I said, "please tell me this doesn't have anything to do with linda lusk." And he just shook his head yes. Reporter: Investigators were now involved. And every night, it was the lead story, a small town, stunned. Another shocking twist in the case of former prosser mayor linda lusk. The media just twisted it and bashed it and just made her seem like such a horrible person. Now some text messages may change the future of this case. There was a certain frenzy to it. There's no doubt about that. Reporter: But kevin lusk would stand by his wife. And we ask him why. I love my wife. I believe her. I support her. And I'm here, probably because somebody actually asked the question, "how the hell could this happen?" Reporter: Linda lusk's husband and children say they know the reason for linda's reckless behavior. They say it stems from her loss at home, another boy in her life, the one she cared for for years, her son, taylor. I would have done anything for him. Reporter: Taylor, born with that disorder, severely disabling his body and his heart, wasn't expected to live more than a week. Remarkably, taylor made it to his teenage years, the center of his mother's life. She was everything for taylor. I mean, she was with him, i mean, 24 hours a day. Reporter: Linda had to feed him, change him, move him. At times, she would even breathe for him. It became something I had to do very frequently was rescue breathing. Reporter: But fate would eventually win on a spring afternoon, when linda left taylor at home with her other children, as she often did to work for a time at her shop. But when she got back, taylor's breathing had stopped one more time, and this time would be the last. I just found him in his bed, not breathing. I blame myself a little bit. That I wasn't there and I could have stopped it. For me it was hard to lose my brother, but I definitely knew it was, I mean, a million times harder for her. Reporter: Linda's family says she changed, falling into a deep depression and guilt over taylor's death. And while she tried to divert her pain by caring for others, in those weeks and months after taylor's death, she did nothing for herself, she did not seek professional help. You have to do something. I'm talking about the grief part, you need to get it handled. You need to go talk to somebody. We didn't. My son died. Of course I was sad. But I didn't realize how bad it was. My whole way of life was gone. I would get up in the morning and go into his room, just automatically, and just go, "oh, he's not there." Reporter: Linda and her husband, kevin, are convinced that into that empty space came that teenager, bubba frank. I felt like I needed to just be what this kid needed. Help him in whatever way i could. And at the time, I don't think it was a conscious decision, b but, yeah, absolutely, I think it felt -- it filled in a need or a void. If she hadn't, you know, suffered the loss from taylor, I'm positive this wouldn't have happened. Reporter: And if that is lia's explanation, some believe bubba frank has his reasons, too. Some pointing to peer pressure, other teens who knew of the text messages and pushed him to push the boundaries even further. Bubba told us he didn't have to push, insisting it was linda who pursued him. The texting just keeps going. And she eventually asked me if i want to take it out of town. Or go to a motel, or we can go to her house, or the basement of her shop. Reporter: At school, some wondered if all of that peer pressure led bubba to embellish what really happened in that bedroom. I didn't like that he was any way, you know, involved with my mom. She's not completely innocent, but she was taken advantage of when she was very vulnerable and upset and sad. Reporter: But in the eyes of prosecutor andy miller, who soon caught wind of bubba's bragging, it did not matter. Linda lusk, he said, was no victim. We charged her with the crime of child molestation in the third degree. There was any never any doubt in our mind that ms.Lusk would be convicted. Reporter: And for her daughter karlie, the only thing worse than the public scandal consuming her family was the thought of her mother going to jail for a very long time. I love her to death. And I don't want my mom to go away. So, I just -- it was scary to think that that was even a

This transcript has been automatically generated and may not be 100% accurate.